Glass-grinding table.



E. BAGNALL.

(MSS GmNDiNG TABLE.

APPLBCAYION FMH) NOVy 30, IMS.

1,1 98,402. lunmmmm. 19,1915

2 SHEETSWSHEET l.

, Wil

E. BAGNALL.

GLASS GRHwDiNG TABLE.

APPLICATION FILED N(}\.30,19i5.

l. D STATES PATENT GFFIC P'i..

EDWARD BAGNALL, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOB T0 ZOHFFEB PLATEGLASS MANUFACTURING COMPANY, OF PITTSBURGH, PENNSYLVANIA, A. CORPO-BATION 0F WEST VIRGINIA.

GLASS-GBINDING TABLE.

Specication of Letters Patent.

Patented Sept. 19, 1916.

Application led November 30, 1915. Serial No. 64,245.

To all whom it may concern:

Be it known that I, EDWARD BAGNALL, a citizen of the United States,residing at Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inGlass- Grinding Tables, of which the following is a specification.

My invention relates to improvements in apparatus for grinding,smoothing and polishing plate glass, and it has for its object toprovide effective and economical means for cushioning and holding theglass plates upon the upper portion of the rotating table, in connectionwith the operations performed by the usual superimposed runners andabrasive material.

In carrying out my invention, the rotatable supporting table is providedwith means for exhausting the air from its interior, anda plurality ofnumerous somewhat closely adjacent specially shaped perforatingapertures communicating with the interior suction cavity of the table,adapted to support a pervious resilient bedding, upon which the glassplates are laid, whereby to provide for the necessary degiee ofVcompression of the bedding and the exhaustion of the air therethroughin effectinga partial vacuum and a resulting holding; air pressure. U

referred embodiments of the invention are shown in the accompanyingdrawings, in which- Fi Ve l is a plan view of the apparatus showingcertain of the exposed aircirculation cavities, a Aportieri of thebedding, and a portion of the glass plates carried thereby. Fig. 2 is avertical cross sectiomindicated by the line Il. Il. of Fig. 1. Fig. 3 isa de tail sectional view, enlarged, showing the action of the apparatuswhen the table is covered with glass plates. Fig. 4 is a similar view,showing the pervious bedding as composed of a plurality of layers ofmaterial, as canton annel. Fi 5 is a similar view, and showing a resilent supporting bed interposed between thel table and the perviousbedding." Fig. 6 isa/view similar larged vertical sectional view of thehollow supporting mast and the surrounding packed -air circulationcollar, taken on the line VII. VII. of Fig. 8. Fig. 8 is a cross sectionon the line VIII. VIII. of Fig. '1.

The rotatable glass supporting table A is ieerably made of an upper wall2 and a ower wall 3, providing an interior air cavity 4. The table ispreferably made in a plurality of sections and divided at the line 5,the sections constituting units of the complete table connected, asshown, and providing for the continuous circulation of the airthroughout its entire interior by means of the central common rotatableair conduit or hollow spindle 6. Said spindlemay be connected with theinterior of the table in any suitable manner, operatingas a hollow mastwhich may act as the main supporting The central hollow spindle 6ismounted in anyzsuitable packed bearing, as indicated, and is inconstant communication b 'suction pipe 10 with any suitable air exausting mechanism. By this arrangement it will be readily seen that theinterior of the table is in suction communication with'. such exhaustingmeans -at all times durngits 'operation. y "A The upper wall 2 of thetable, which is level and substantially smooth, is provided withnumerous somewhat adjacent coniform-shaped openings 11 flaring outwardlyand providing a series of cuprshaped downwardly tapering cavitiesthroughout the entire supporting area of the table, -each of which is incommunication with the main interior cavity 4 by means of a reducedcommunicating port 12.

`For the purpose of providing a supporting bed for the plate glass, I'lay completely.

over the entire area of the table A, and covering all of the cavitieslllfa bedding 13 consisting of canton flannel, gliraiiv"telt, cloth,

or other suitable oervious material having ullicient body to providea'eompressible supporting cushion `for the plates 14. Sur- ."ounding theperiphery ot' the table and closing the exposed edges of bedding 13 tothe atmosphere, after tlie plates 14 are. laid, l may, it desired,provide a surrounding packing 15, which may be of'- plaster of Paris orother suitable material easily appliedor removed, and which wille'ectually seal the edges of the bedding 18 against access of air, upon.creation of the suction vacuum. The. packing 15 is however, notabsolutely necessary.` The table being thus covered and the plates beingin position, exhaustion of the air from cavity 4 will create a suctionof the air through tiie'pervious beddingr 13 and cavities 11v and ports12, resulting in a. corresponding external. air pressure. which willbind :the platesli firmly upon the bedding.. i

At locations corresponding tothe openings l1, the bedding will besomewhat depressednnder outside air pressure, as indicated at 16',thereby )roviding collecting pockets for Nthe air which is exhaustedfrom beneath the. entire surrouiuling area of the plates hert-ver.theyare in close contact with the other rou'iyu'essed supporting portionsofthe bedding. B v this means the exhaustion othe air isfaunilitated andits conetant action l in vmaintaining suctionv and resnltingrcompression upon the plates is maintained.

The' pervious bedding layer 13 may be in one continuous pietxf.. laidacrossthe entire surfac'eof thestable. butif necessary, it may be in two.or more parts, having tightly contacting edges. whereby age, and itwill thusserve to provide a prat'4 tically uniform, level,v resilient'support for the glassplatesl ln practice, l have used a plurality ofcircular layers 13 of canton flannel, made of normal widths of material,laid edge'to edge and stitched, as indicated at 13". the seams thus vnotincreasingY the normal thickness. and preferably laid across the. 'seamsof the next' under and upper layer, as clearly shown' in Fig. 1. Spacesbetween the plates M may, itdesired'.l be filled with narrow strips ofwood, plaster of Paris, or other suitable sealing material. as iscommonly ldone in ordinary bedding of the glass, without, hoivever,allowing any of the plaster to accmnula'te beneath-'the plates or `tointerfere. with t-he porosity of the bedding. The bedding inay 'he's mlcd .with water, if desired`v` or `riff-,rely dampened or used dry,depending upon the conditions present or the material used. l have alsoused oil in treatv ingv the flannel layers with goed success. the

oil tendini! to add to the resistance of theflannel to passage ofmoist-ure, and increas 'ing its flexibility. The degree of suction or offlannel 13,

to avoid undue leak.- Y

may be variously changed or modified b v the skilled mechanic.

ln Fig.' 5, l show a supporting mat or pad 17 of rubber or otherSuitable somewhat resilient material having a flat under and uppersurface, and a. series of transverse openings 18 corresponding .to andregistering with the suction openings 1.1. lly this means l prevent theinjurious ellect of inequalities in the surface of the table and retainthe full advantage ofthe upper cushion as described. Said ligure alsoshows the edges of the pervious bedding;r as exposed, the suction beingordinarily ample to overcome any lat-eral leakage.

ln Fig. (i the several parts ofthe table and its driving mechanism arethe same as above described, indicated by correspoiidingr numerulsprimed. the vhollow mast also having a supplen'u'utal bearing lllaud thegearing being driven b v a motor 20 and suitable intervening gearing 21.22. lqurroumling the mast. l and forming u rotatable.. hart with it isunemlu'ucing collar 23 through which extends into the hollow interior ofthe.

tween flanges .13 is a n annular cavityl() thus in constantcommunication with the interior of the hollow mast. and also incommunica-- tion with the air exhausting mechanism lby pipe 10. Saidpipe leads to a vacuum tank 5l] with un intervening b v-pass4 pipe 51'.leading tf: a water collecting tank 325 havinga valve controlledexliaustpipe 154, for collection and disposal of any water which mayfind its \va \r to the, suctioli pipe. An air pump f'l is connected bypipe G with'thi: vacuum tank ill, which is alsoprovided with a vacuumgage 2li".

The, advantages of the. invention wil-l be readily luiderstoml andappreciated by all those familiar with the construction .and operationof glass grinding und polishing mechanism. lt obviates the necessity ofthe usual -cemenling or other laborious and expensive methods in voguefor holding the glassplates to the table, providing for their easy andquick removal or reversal upon admission of air to the interior; itobviates the danger of breakage incideht to the placing of the glassplates directly upon the metal Q!) adapted to be` surface. of the table,and it provides a certain degree of cushioning action beneath therotating superimposed runners, While compensating for any unevenness orinaccuracy in the plane of the table.

What I claim is:

1. A rotatable glass grinding table having a hollow interior and aplurality of adjal cent circular upwardly diverging openings throughtheupper wall of the table, means for exhausting the air from the hollowinterior, and 'a superimposed porous bedding of compressible material.

2. A rotatable glass grinding table having a hollow interior and aplurality of adjacent circular upwardly diverging openings through theupper Wall of the table, means for exhausting the airfrom the hollowinterior, a superimposed porous bedding of compressible material, and asurrounding peripheral air sealing covering for the edges of saidbedding.

3. A rotatable glass grinding table having a hollow interior and aplurality of adjacent openings through the upper wall of the table,means for exhausting the air from the hollow interior, a layer ofimpervious material on the surface of the table having openingsregistering with the table openings, and a superimposed bedding ofoompressible material.

4. In a rotatable glass supporting table of the class described havingan interior vacuum cavity and an upper supporting wall provided with aplurality of adjacent upwardly flaring transverse openings communicatingthrough diminished openings with the interior; the combination with saidupper wall, of a layer of compressible porous material, and glass plateslaid thereovern 5. In a rotatable glass supporting table of the classdescribed having an interior vacuum cavity and an upper supporting Wallprovided with a plurality of adjacent upwardly flaring transverseopenings communicating through diminished openings with the interior;the combination with Said upper wall, of a layer of compressible porousmaterial`r glass plates laid thereover, and a surrounding sealingmaterial inclosing the peripheral edges of the bedding and glass platesand preventingA the entrance of air.

In testimony whereof I hereunto affix my signature in the presence oftwo witnesses.

- y EDWARD BAGNALL. Witnesses:

YV. A. HECKMAN, C. M. CLARKE.

